Hatching glands in Cephalopods: Origin, differentiation and degradation by programmed cell death

Author(s)
Norbert Cyran, Janek Von Byern, Yannick Städler, Jürg Schönenberger, Waltraud Klepal
Abstract

Hatching of embryos from their eggs begins when unicellular glands release hatching enzymes. The enzymes weaken the chorionic membrane, which is then easily broken by the movement of the embryo. Although numerous morphological and biochemical studies exist on the hatching glands of invertebrates (such as sea urchins, insects, ascidians) and vertebrates (teleosts, amphibians, and mammals), little is known about the morphology of the hatching glands (Hoyle organ) in cephalopod hatchlings.
In this study, the internal gland structure and the external appearance of the Hoyle organ is compared among several cephalopod species (Idiosepius pygmaeus; Euprymna scolopes; Sepia officinalis; Loligo gahi; Sepioteuthis lessoniana; Architeuthis sp.; Octopus vulgaris; Tremoctopus gracilis; Argonauta hians). In almost all cases the glandular system is restricted to the posterior part of the dorsal mantle surface. Only Octopus and Argonauta lack a specific glandular structure in this body region and the animals apparently use other mechanisms to penetrate the egg layers.
In all decapod species (Idiosepius; Euprymna; Sepia; Loligo; Sepioteuthis; Architeuthis) as well as in Tremoctopus only one specific cell type is present in the Hoyle organ, which synthesizes granular material. The secretory droplets are more or less uniform in electron density in Idiosepius, Euprymna and Tremoctopus but exhibit translucent inclusions in the other decapods. The time of gland development, first synthesis of secretory products and later degeneration after hatching vary between the species

Organisation(s)
Department of Botany and Biodiversity Research
Publication date
11-2015
Austrian Fields of Science 2012
106010 Developmental biology
Portal url
https://ucris.univie.ac.at/portal/en/publications/hatching-glands-in-cephalopods-origin-differentiation-and-degradation-by-programmed-cell-death(e5cee701-9826-4092-9d68-c526a5ce1d57).html